On 05/27/2010 12:51 PM, Sebastian Tennant wrote:

Quoth Frank Gore :

There's more to it than just the PNG format, and this isn't really a Gimp thing:

http://homepage.ntlworld.com/bobosola/

Many thanks to all respondents.

It turns out there are two kinds of transparency; binary & alpha channel. IE6 can handle binary but not alpha channel.

Something I read next (I forget what/where it was now) made a link between 'binary' and 'indexed' (neither term really meaning anything to me) so I used Gimp to creat a new image, chose to fill it with a transparent background and then switched to Indexed mode (as opposed to RGB or Greyscale) before exporting to PNG, and it worked!

So, in short, if you want your transparent PNGs to work in IE6, switch to indexed mode before you export... it really does seem to be as simple as that.

Sebastian

Can't doing this result in some loss of image quality? Sometimes I'll make PNGs with a drop shadow and transparency and when I convert the image to indexed mode, the drop shadow quality suffers.

Peace...

Tom

On 05/27/2010 01:47 PM, Stefan Maerz wrote:

On 5/27/2010 3:38 PM, Tom Williams wrote:

Can't doing this result in some loss of image quality? Sometimes I'll make PNGs with a drop shadow and transparency and when I convert the image to indexed mode, the drop shadow quality suffers.

Peace...

Tom

On 05/27/2010 02:00 PM, niski wrote:

W dniu 2010-05-27 22:38, Tom Williams pisze:

On 05/27/2010 12:51 PM, Sebastian Tennant wrote:

Quoth Frank Gore:

There's more to it than just the PNG format, and this isn't really a Gimp
thing:

http://homepage.ntlworld.com/bobosola/

Many thanks to all respondents.

It turns out there are two kinds of transparency; binary& alpha channel. IE6
can handle binary but not alpha channel.

Something I read next (I forget what/where it was now) made a link between
'binary' and 'indexed' (neither term really meaning anything to me) so I used
Gimp to creat a new image, chose to fill it with a transparent background and
then switched to Indexed mode (as opposed to RGB or Greyscale) before exporting
to PNG, and it worked!

So, in short, if you want your transparent PNGs to work in IE6, switch to
indexed mode before you export... it really does seem to be as simple as that.

Sebastian

Can't doing this result in some loss of image quality? Sometimes I'll make PNGs with a drop shadow and transparency and when I convert the image to indexed mode, the drop shadow quality suffers.

Peace...

Tom

On 05/27/2010 03:03 PM, Branko Vukelic wrote:

On Thu, May 27, 2010 at 10:38 PM, Tom Williams wrote:

Can't doing this result in some loss of image quality? Sometimes I'll make PNGs with a drop shadow and transparency and when I convert the image to indexed mode, the drop shadow quality suffers.

There are ways to do this correctly and keep the image visually similar to the original 24-bit PNG (the one with alpha).

You must know the color of the background on which you'll be putting the 8-bit PNG (binary transparency) before you can do so, though. Once you know the background color:

1. Create a layer filled with background color 2. Put the layer behind the image with drop shadow 3. Flatten the image and add alpha to the only remaining layer 4. Use select by color tool and click somewhere where background shows though 5. Clear the selection (delete it)
6. Now save the result as 8-bit PNG and it should work

(Of course, it'll be clearer when you actually do these steps.)

HTH

Thanks for the info! :)

Peace...

Tom

On 05/27/2010 02:56 PM, Frank Gore wrote:

On Thu, May 27, 2010 at 4:38 PM, Tom Williams wrote:

Can't doing this result in some loss of image quality? Sometimes I'll make PNGs with a drop shadow and transparency and when I convert the image to indexed mode, the drop shadow quality suffers.

The problem with indexed colour is that the PNG format is still technically limited to 8bit in its colour palette in this mode, just like GIF was. So yes, you can lose tons of quality and colour.

Thing is, IE6 is pretty much deprecated at this point anyways. Most new templates for things like Joomla, Drupal et al do not include full support for IE6 anymore. Now if only people would stop installing old versions of Windows XP, we'd all be better for it :)

Thanks!

Peace...

Tom

On Fri, May 28, 2010 at 12:19 AM, Tom Williams wrote:

Thanks for the info!  :)

Tom, there's no need to spam the list with thanks (as far as I'm concerned), and quote whole messages just to say "Thanks". ;)